========================================================================
* README
========================================================================

NAME

    Importer - Alternative but compatible interface to modules that export
    symbols.

DESCRIPTION

    This module acts as a layer between Exporter and modules which consume
    exports. It is feature-compatible with Exporter, plus some much needed
    extras. You can use this to import symbols from any exporter that
    follows Exporters specification. The exporter modules themselves do not
    need to use or inherit from the Exporter module, they just need to set
    @EXPORT and/or other variables.

SYNOPSIS

        # Import defaults
        use Importer 'Some::Module';

        # Import a list
        use Importer 'Another::Module' => qw/foo bar baz/;

        # Import a specific version:
        use Importer 'That::Module' => '1.00';

        # Require a sepcific version of Importer
        use Importer 0.001, 'Foo::Bar' => qw/a b c/;

        foo()
        bar()
        baz()

        # Remove all subroutines imported by Importer
        no Importer;

        # Import symbols into variables
        my $croak = Importer->get_one(Carp => qw/croak/);
        $croak->("This will croak");

        my $CARP = Importer->get(Carp => qw/croak confess cluck/);
        $CARP->{croak}->("This will croak");
        $CARP->{cluck}->("This will cluck");
        $CARP->{confess}->("This will confess");

WHY?

    There was recently a discussion on p5p about adding features to
    Exporter. This conversation raised some significant concerns, those are
    listed here, in addition to others.

    The burden is on export consumers to specify a version of Exporter

      Adding a feature to Exporter means that any consumer module that
      relies on the new features must depend on a specific version of
      Exporter. This seems somewhat backwards since Exporter is used by the
      module you are importing from.

    Exporter.pm is really old/crazy code

      Not much more to say here. It is very old, it is very crazy, and if
      you break it you break EVERYTHING.

    Using a modules import() for exporting makes it hard to give it other
    purposes

      It is not unusual for a module to want to export symbols and provide
      import behaviors. It is also not unusual for a consumer to only want
      1 or the other. Using this module you can import symbols without also
      getting the import() side effects.

      In addition, moving forward, modules can specify exports and have a
      custom import() without conflating the two. A module can tell you to
      use Importer to get the symbols, and to use the module directly for
      behaviors. A module could also use Importer within its own import()
      method without the need to subclass Exporter, or bring in its
      import() method.

    There are other exporter modules on cpan

      This module normally assumes an exporter uses Exporter, so it looks
      for the variables and methods Exporter expects. However, other
      exporters on cpan can override this using the IMPORTER_MENU() hook.

COMPATIBILITY

    This module aims for 100% compatibility with every feature of Exporter,
    plus added features such as import renaming.

    If you find something that works differently, or not at all when
    compared to Exporter please report it as a bug, unless it is noted as
    an intentional feature (like import renaming).

IMPORT PARAMETERS

        use Importer $IMPORTER_VERSION, $FROM_MODULE, $FROM_MODULE_VERSION, \&SET_SYMBOL, @SYMBOLS;

    $IMPORTER_VERSION (optional)

      If you provide a numeric argument as the first argument it will be
      treated as a version number. Importer will do a version check to make
      sure it is at least at the requested version.

    $FROM_MODULE (required)

      This is the only required argument. This is the name of the module to
      import symbols from.

    $FROM_MODULE_VERSION (optional)

      Any numeric argument following the $FROM_MODULE will be treated as a
      version check against $FROM_MODULE.

    \&SET_SYMBOL (optional)

      Normally Importer will put the exports into your namespace. This is
      usually done via a more complex form of *name = $ref. If you do NOT
      want this to happen then you can provide a custom sub to handle the
      assignment.

      This is an example that uses this feature to put all the exports into
      a lexical hash instead of modifying the namespace (This is how the
      get() method is implemented).

          my %CARP;
          use Importer Carp => sub {
              my ($name, $ref) = @_;
              $CARP{$name} = $ref;
          };

          $CARP{cluck}->("This will cluck");
          $CARP{croak}->("This will croak");

      The first two arguments to the custom sub are the name (no sigil),
      and the reference. The additional arguments are key/value pairs:

          sub set_symbol {
              my ($name, $ref, %info) = @_;
          }

      $info{from}

	Package the symbol comes from.

      $info{into}

	Package to which the symbol should be added.

      $info{sig}

	The sigil that should be used.

      $info{spec}

	Extra details.

      $info{symbol}

	The original symbol name (with sigil) from the original package.

    @SYMBOLS (optional)

      Symbols you wish to import. If no symbols are specified then the
      defaults will be used. You may also specify tags using the ':'
      prefix.

SUPPORTED FEATURES

 TAGS

    You can define/import subsets of symbols using predefined tags.

        use Importer 'Some::Thing' => ':tag';

    Importer will automatically populate the :DEFAULT tag for you. Importer
    will also give you an :ALL tag with ALL exports so long as the exporter
    does not define a :ALL tag already.

 /PATTERN/ or qr/PATTERN/

    You can import all symbols that match a pattern. The pattern can be
    supplied a string starting and ending with '/', or you can provide a
    qr/../ reference.

        use Importer 'Some::Thing' => '/oo/';

        use Importer 'Some::Thing' => qr/oo/;

 EXCLUDING SYMBOLS

    You can exclude symbols by prefixing them with '!'.

        use Importer 'Some::Thing'
            '!foo',         # Exclude one specific symbol
            '!/pattern/',   # Exclude all matching symbols
            '!' => qr/oo/,  # Exclude all that match the following arg
            '!:tag';        # Exclude all in tag

 RENAMING SYMBOLS AT IMPORT

    This is a new feature, Exporter does not support this on its own.

    You can rename symbols at import time using a specification hash
    following the import name:

        use Importer 'Some::Thing' => (
            foo => { -as => 'my_foo' },
        );

    You can also add a prefix and/or postfix:

        use Importer 'Some::Thing' => (
            foo => { -prefix => 'my_' },
        );

    Using this syntax to set prefix and/or postfix also works on tags and
    patterns that are specified for import, in which case the
    prefix/postfix is applied to all symbols from the tag/patterm.

 CUSTOM EXPORT ASSIGNMENT

    This lets you provide an alternative to the *name = $ref export
    assignment. See the list of parameters to import()

 UNIMPORTING

    See "UNIMPORT PARAMETERS".

 ANONYMOUS EXPORTS

    See "%EXPORT_ANON".

 GENERATED EXPORTS

    See "%EXPORT_GEN".

UNIMPORT PARAMETERS

        no Importer;    # Remove all subs brought in with Importer

        no Importer qw/foo bar/;    # Remove only the specified subs

    Only subs can be unimported.

    You can only unimport subs imported using Importer.

SUPPORTED VARIABLES

 @EXPORT

    This is used exactly the way Exporter uses it.

    List of symbols to export. Sigil is optional for subs. Symbols listed
    here are exported by default. If possible you should put symbols in
    @EXPORT_OK instead.

        our @EXPORT = qw/foo bar &baz $BAT/;

 @EXPORT_OK

    This is used exactly the way Exporter uses it.

    List of symbols that can be imported. Sigil is optional for subs.
    Symbols listed here are not exported by default. This is preferred over
    @EXPORT.

        our @EXPORT_OK = qw/foo bar &baz $BAT/;

 %EXPORT_TAGS

    This module supports tags exactly the way Exporter does.

        use Importer 'Some::Thing'  => ':DEFAULT';

        use Importer 'Other::Thing' => ':some_tag';

    Tags can be specified this way:

        our %EXPORT_TAGS = (
            oos => [qw/foo boo zoo/],
            ees => [qw/fee bee zee/],
        );

 @EXPORT_FAIL

    This is used exactly the way Exporter uses it.

    Use this to list subs that are not available on all platforms. If
    someone tries to import one of these, Importer will hit your
    $from->export_fail(@items) callback to try to resolve the issue. See
    Exporter for documentation of this feature.

        our @EXPORT_FAIL = qw/maybe_bad/;

 %EXPORT_ANON

    This is new to this module, Exporter does not support it.

    This allows you to export symbols that are not actually in your package
    symbol table. The keys should be the symbol names, the values are the
    references for the symbols.

        our %EXPORT_ANON = (
            '&foo' => sub { 'foo' }
            '$foo' => \$foo,
            ...
        );

 %EXPORT_GEN

    This is new to this module, Exporter does not support it.

    This allows you to export symbols that are generated on export. The key
    should be the name of a symbol. The value should be a coderef that
    produces a reference that will be exported.

    When the generators are called they will receive 2 arguments, the
    package the symbol is being exported into, and the symbol being
    imported (name may or may not include sigil for subs).

        our %EXPORT_GEN = (
            '&foo' => sub {
                my $from_package = shift;
                my ($into_package, $symbol_name) = @_;
                ...
                return sub { ... };
            },
            ...
        );

 %EXPORT_MAGIC

    This is new to this module. Exporter does not support it.

    This allows you to define custom actions to run AFTER an export has
    been injected into the consumers namespace. This is a good place to
    enable parser hooks like with Devel::Declare. These will NOT be run if
    a consumer uses a custom assignment callback.

        our %EXPORT_MAGIC = (
            foo => sub {
                my $from = shift;    # Should be the package doing the exporting
                my %args = @_;

                my $into      = $args{into};         # Package symbol was exported into
                my $orig_name = $args{orig_name};    # Original name of the export (in the exporter)
                my $new_name  = $args{new_name};     # Name the symbol was imported as
                my $ref       = $args{ref};          # The reference to the symbol

                ...; # whatever you want, return is ignored.
            },
        );

CLASS METHODS

    Importer->import($from)

    Importer->import($from, $version)

    Importer->import($from, @imports)

    Importer->import($from, $from_version, @imports)

    Importer->import($importer_version, $from, ...)

      This is the magic behind use Importer ....

    Importer->import_into($from, $into, @imports)

    Importer->import_into($from, $level, @imports)

      You can use this to import symbols from $from into $into. $into may
      either be a package name, or a caller level to get the name from.

    Importer->unimport()

    Importer->unimport(@sub_name)

      This is the magic behind no Importer ....

    Importer->unimport_from($from, @sub_names)

    Importer->unimport_from($level, @sub_names)

      This lets you remove imported symbols from $from. $from my be a
      package name, or a caller level.

    my $exports = Importer->get($from, @imports)

      This returns hashref of { $name => $ref } for all the specified
      imports.

      $from should be the package from which to get the exports.

    my @export_refs = Importer->get_list($from, @imports)

      This returns a list of references for each import specified. Only the
      export references are returned, the names are not.

      $from should be the package from which to get the exports.

    $export_ref = Importer->get_one($from, $import)

      This returns a single reference to a single export. If you provide
      multiple imports then only the LAST one will be used.

      $from should be the package from which to get the exports.

USING WITH OTHER EXPORTER IMPLEMENTATIONS

    If you want your module to work with Importer, but you use something
    other than Exporter to define your exports, you can make it work be
    defining the IMPORTER_MENU method in your package. As well other
    exporters can be updated to support Importer by putting this sub in
    your package. IMPORTER_MENU() must be defined in your package, not a
    base class!

        sub IMPORTER_MENU {
            my $class = shift;
            my ($into, $caller) = @_;

            return (
                export       => \@EXPORT,          # Default exports
                export_ok    => \@EXPORT_OK,       # Other allowed exports
                export_tags  => \%EXPORT_TAGS,     # Define tags
                export_fail  => \@EXPORT_FAIL,     # For subs that may not always be available
                export_anon  => \%EXPORT_ANON,     # Anonymous symbols to export
                export_magic => \%EXPORT_MAGIC,    # Magic to apply after a symbol is exported

                generate   => \&GENERATE,          # Sub to generate dynamic exports
                                                   # OR
                export_gen => \%EXPORT_GEN,        # Hash of builders, key is symbol
                                                   # name, value is sub that generates
                                                   # the symbol ref.
            );
        }

        sub GENERATE {
            my ($symbol) = @_;

            ...

            return $ref;
        }

    All exports must be listed in either @EXPORT or @EXPORT_OK, or be keys
    in %EXPORT_GEN or %EXPORT_ANON to be allowed. 'export_tags',
    'export_fail', 'export_anon', 'export_gen', and 'generate' are
    optional. You cannot combine 'generate' and 'export_gen'.

    Note: If your GENERATE sub needs the $class, $into, or $caller then
    your IMPORTER_MENU() method will need to build an anonymous sub that
    closes over them:

        sub IMPORTER_MENU {
            my $class = shift;
            my ($into, $caller) = @_;

            return (
                ...
                generate => sub { $class->GENERATE($into, $caller, @_) },
            );
        }

OO Interface

        use Importer;

        my $imp = Importer->new(from => 'Some::Exporter');

        $imp->do_import('Destination::Package');
        $imp->do_import('Another::Destination', @symbols);

    Or, maybe more useful:

        my $imp = Importer->new(from => 'Carp');
        my $croak = $imp->get_one('croak');
        $croak->("This will croak");

 OBJECT CONSTRUCTION

    $imp = Importer->new(from => 'Some::Exporter')

    $imp = Importer->new(from => 'Some::Exporter', caller => [$package,
    $file, $line])

      This is how you create a new Importer instance. from =>
      'Some::Exporter' is the only required argument. You may also specify
      the caller => [...] arrayref, which will be used only for error
      reporting. If you do not specify a caller then Importer will attempt
      to find the caller dynamically every time it needs it (this is slow
      and expensive, but necessary if you intend to re-use the object.)

 OBJECT METHODS

    $imp->do_import($into)

    $imp->do_import($into, @symbols)

      This will import from the objects from package into the $into
      package. You can provide a list of @symbols, or you can leave it
      empty for the defaults.

    $imp->do_unimport()

    $imp->do_unimport(@symbols)

      This will remove imported symbols from the objects from package. If
      you specify a list of @symbols then only the specified symbols will
      be removed, otherwise all symbols imported using Importer will be
      removed.

      Note: Please be aware of the difference between do_import() and
      do_unimport(). For import 'from' us used as the origin, in unimport
      it is used as the target. This means you cannot re-use an instance to
      import and then unimport.

    ($into, $versions, $exclude, $symbols, $set) =
    $imp->parse_args('Dest::Package')

    ($into, $versions, $exclude, $symbols, $set) =
    $imp->parse_args('Dest::Package', @symbols)

      This parses arguments. The first argument must be the destination
      package. Other arguments can be a mix of symbol names, tags,
      patterns, version numbers, and exclusions.

    $caller_ref = $imp->get_caller()

      This will find the caller. This is mainly used for error reporting.
      IF the object was constructed with a caller then that is what is
      returned, otherwise this will scan the stack looking for the first
      call that does not originate from a package that ISA Importer.

    $imp->carp($warning)

      Warn at the callers level.

    $imp->croak($exception)

      Die at the callers level.

    $from_package = $imp->from()

      Get the from package that was specified at construction.

    $file = $imp->from_file()

      Get the filename for the from package.

    $imp->load_from()

      This will load the from package if it has not been loaded already.
      This uses some magic to ensure errors in the load process are
      reported to the caller.

    $menu_hr = $imp->menu($into)

      Get the export menu built from, or provided by the from package. This
      is cached after the first time it is called. Use $imp->reload_menu()
      to refresh it.

      The menu structure looks like this:

          $menu = {
              # every valid export has a key in the lookup hashref, value is always
              # 1, key always includes the sigil
              lookup => {'&symbol_a' => 1, '$symbol_b' => 1, ...},

              # most exports are listed here, symbol name with sigil is key, value is
              # a reference to the symbol. If a symbol is missing it may be generated.
              exports => {'&symbol_a' => \&symbol_a, '$symbol_b' => \$symbol_b, ...},

              # Hashref of tags, tag name (without ':' prefix) is key, value is an
              # arrayref of symbol names, subs may have a sigil, but are not required
              # to.
              tags => { DEFAULT => [...], foo => [...], ... },

              # Magic to apply
              magic => { foo => sub { ... }, ... },

              # This is a hashref just like 'lookup'. Keys are symbols which may not
              # always be available. If there are no symbols in this category then
              # the value of the 'fail' key will be undef instead of a hashref.
              fail => { '&iffy_symbol' => 1, '\&only_on_linux' => 1 },
              # OR fail => undef,

              # If present, this subroutine knows how to generate references for the
              # symbols listed in 'lookup', but missing from 'exports'. References
              # this returns are NEVER cached.
              generate => sub { my $sym_name = shift; ...; return $symbol_ref },
          };

    $imp->reload_menu($into)

      This will reload the export menu from the from package.

    my $exports = $imp->get(@imports)

      This returns hashref of { $name => $ref } for all the specified
      imports.

    my @export_refs = $imp->get_list(@imports)

      This returns a list of references for each import specified. Only the
      export references are returned, the names are not.

    $export_ref = $imp->get_one($import)

      This returns a single reference to a single export. If you provide
      multiple imports then only the LAST one will be used.

FUNCTIONS

    These can be imported:

        use Importer 'Importer' => qw/import optimal_import/;

    $bool = optimal_import($from, $into, \@caller, @imports)

      This function will attempt to import @imports from the $from package
      into the $into package. @caller needs to have a package name,
      filename, and line number. If this function fails then no exporting
      will actually happen.

      If the import is successful this will return true.

      If the import is unsuccessful this will return false, and no
      modifications to the symbol table will occur.

    $class->import(@imports)

      If you write class intended to be used with Importer, but also need
      to provide a legacy import() method for direct consumers of your
      class, you can import this import() method.

          package My::Exporter;

          # This will give you 'import()' much like 'use base "Exporter";'
          use Importer 'Importer' => qw/import/;

          ...

SOURCE

    The source code repository for Importer can be found at
    http://github.com/exodist/Importer.

MAINTAINERS

    Chad Granum <exodist@cpan.org>

AUTHORS

    Chad Granum <exodist@cpan.org>

COPYRIGHT

    Copyright 2015 Chad Granum <exodist7@gmail.com>.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    See http://dev.perl.org/licenses/


========================================================================
* README.md
========================================================================

# NAME

Importer - Alternative but compatible interface to modules that export symbols.

# DESCRIPTION

This module acts as a layer between [Exporter](https://metacpan.org/pod/Exporter)
and modules which consume
exports. It is feature-compatible with [Exporter](https://metacpan.org/pod/Exporter),
plus some much needed
extras. You can use this to import symbols from any exporter that follows
[Exporter](https://metacpan.org/pod/Exporter)s specification. The exporter modules
themselves do not need to use
or inherit from the [Exporter](https://metacpan.org/pod/Exporter) module, they just
need to set `@EXPORT` and/or
other variables.

# SYNOPSIS

    # Import defaults
    use Importer 'Some::Module';

    # Import a list
    use Importer 'Another::Module' => qw/foo bar baz/;

    # Import a specific version:
    use Importer 'That::Module' => '1.00';

    # Require a sepcific version of Importer
    use Importer 0.001, 'Foo::Bar' => qw/a b c/;

    foo()
    bar()
    baz()

    # Remove all subroutines imported by Importer
    no Importer;

    # Import symbols into variables
    my $croak = Importer->get_one(Carp => qw/croak/);
    $croak->("This will croak");

    my $CARP = Importer->get(Carp => qw/croak confess cluck/);
    $CARP->{croak}->("This will croak");
    $CARP->{cluck}->("This will cluck");
    $CARP->{confess}->("This will confess");

# WHY?

There was recently a discussion on p5p about adding features to [Exporter](https://metacpan.org/pod/Exporter).
This conversation raised some significant concerns, those are listed here, in
addition to others.

- The burden is on export consumers to specify a version of Exporter

    Adding a feature to [Exporter](https://metacpan.org/pod/Exporter) means that
    any consumer module that relies on
    the new features must depend on a specific version of [Exporter](https://metacpan.org/pod/Exporter). This seems
    somewhat backwards since [Exporter](https://metacpan.org/pod/Exporter) is used
    by the module you are importing
    from.

- Exporter.pm is really old/crazy code

    Not much more to say here. It is very old, it is very crazy, and if you break
    it you break EVERYTHING.

- Using a modules import() for exporting makes it hard to give it other purposes

    It is not unusual for a module to want to export symbols and provide import
    behaviors. It is also not unusual for a consumer to only want 1 or the other.
    Using this module you can import symbols without also getting the `import()`
    side effects.

    In addition, moving forward, modules can specify exports and have a custom
    `import()` without conflating the two. A module can tell you to use Importer
    to get the symbols, and to use the module directly for behaviors. A module
    could also use Importer within its own `import()` method without the need to
    subclass [Exporter](https://metacpan.org/pod/Exporter), or bring in its `import()` method.

- There are other exporter modules on cpan

    This module normally assumes an exporter uses [Exporter](https://metacpan.org/pod/Exporter),
    so it looks for the
    variables and methods [Exporter](https://metacpan.org/pod/Exporter) expects. However,
    other exporters on cpan can
    override this using the `IMPORTER_MENU()` hook.

# COMPATIBILITY

This module aims for 100% compatibility with every feature of [Exporter](https://metacpan.org/pod/Exporter), plus
added features such as import renaming.

If you find something that works differently, or not at all when compared to
[Exporter](https://metacpan.org/pod/Exporter) please report it as a bug, unless it
is noted as an intentional
feature (like import renaming).

# IMPORT PARAMETERS

    use Importer $IMPORTER_VERSION, $FROM_MODULE, $FROM_MODULE_VERSION, \&SET_SYMBOL, @SYMBOLS;

- $IMPORTER\_VERSION (optional)

    If you provide a numeric argument as the first argument it will be treated as a
    version number. Importer will do a version check to make sure it is at least at
    the requested version.

- $FROM\_MODULE (required)

    This is the only required argument. This is the name of the module to import
    symbols from.

- $FROM\_MODULE\_VERSION (optional)

    Any numeric argument following the `$FROM_MODULE` will be treated as a version
    check against `$FROM_MODULE`.

- \\&SET\_SYMBOL (optional)

    Normally Importer will put the exports into your namespace. This is usually
    done via a more complex form of `*name = $ref`. If you do NOT want this to
    happen then you can provide a custom sub to handle the assignment.

    This is an example that uses this feature to put all the exports into a lexical
    hash instead of modifying the namespace (This is how the `get()` method is
    implemented).

        my %CARP;
        use Importer Carp => sub {
            my ($name, $ref) = @_;
            $CARP{$name} = $ref;
        };

        $CARP{cluck}->("This will cluck");
        $CARP{croak}->("This will croak");

    The first two arguments to the custom sub are the name (no sigil), and the
    reference. The additional arguments are key/value pairs:

        sub set_symbol {
            my ($name, $ref, %info) = @_;
        }

    - $info{from}

        Package the symbol comes from.

    - $info{into}

        Package to which the symbol should be added.

    - $info{sig}

        The sigil that should be used.

    - $info{spec}

        Extra details.

    - $info{symbol}

        The original symbol name (with sigil) from the original package.

- @SYMBOLS (optional)

    Symbols you wish to import. If no symbols are specified then the defaults will
    be used. You may also specify tags using the ':' prefix.

# SUPPORTED FEATURES

## TAGS

You can define/import subsets of symbols using predefined tags.

    use Importer 'Some::Thing' => ':tag';

[Importer](https://metacpan.org/pod/Importer) will automatically populate the `:DEFAULT`
tag for you.
[Importer](https://metacpan.org/pod/Importer) will also give you an `:ALL` tag with
ALL exports so long as the
exporter does not define a `:ALL` tag already.

## /PATTERN/ or qr/PATTERN/

You can import all symbols that match a pattern. The pattern can be supplied a
string starting and ending with '/', or you can provide a `qr/../` reference.

    use Importer 'Some::Thing' => '/oo/';

    use Importer 'Some::Thing' => qr/oo/;

## EXCLUDING SYMBOLS

You can exclude symbols by prefixing them with '!'.

    use Importer 'Some::Thing'
        '!foo',         # Exclude one specific symbol
        '!/pattern/',   # Exclude all matching symbols
        '!' => qr/oo/,  # Exclude all that match the following arg
        '!:tag';        # Exclude all in tag

## RENAMING SYMBOLS AT IMPORT

_This is a new feature,_ [Exporter](https://metacpan.org/pod/Exporter) _does not
support this on its own._

You can rename symbols at import time using a specification hash following the
import name:

    use Importer 'Some::Thing' => (
        foo => { -as => 'my_foo' },
    );

You can also add a prefix and/or postfix:

    use Importer 'Some::Thing' => (
        foo => { -prefix => 'my_' },
    );

Using this syntax to set prefix and/or postfix also works on tags and patterns
that are specified for import, in which case the prefix/postfix is applied to
all symbols from the tag/patterm.

## CUSTOM EXPORT ASSIGNMENT

This lets you provide an alternative to the `*name = $ref` export assignment.
See the list of [parameters](#import-parameters) to `import()`

## UNIMPORTING

See ["UNIMPORT PARAMETERS"](#unimport-parameters).

## ANONYMOUS EXPORTS

See ["%EXPORT\_ANON"](#export_anon).

## GENERATED EXPORTS

See ["%EXPORT\_GEN"](#export_gen).

# UNIMPORT PARAMETERS

    no Importer;    # Remove all subs brought in with Importer

    no Importer qw/foo bar/;    # Remove only the specified subs

**Only subs can be unimported**.

**You can only unimport subs imported using Importer**.

# SUPPORTED VARIABLES

## @EXPORT

This is used exactly the way [Exporter](https://metacpan.org/pod/Exporter) uses it.

List of symbols to export. Sigil is optional for subs. Symbols listed here are
exported by default. If possible you should put symbols in `@EXPORT_OK`
instead.

    our @EXPORT = qw/foo bar &baz $BAT/;

## @EXPORT\_OK

This is used exactly the way [Exporter](https://metacpan.org/pod/Exporter) uses it.

List of symbols that can be imported. Sigil is optional for subs. Symbols
listed here are not exported by default. This is preferred over `@EXPORT`.

    our @EXPORT_OK = qw/foo bar &baz $BAT/;

## %EXPORT\_TAGS

This module supports tags exactly the way [Exporter](https://metacpan.org/pod/Exporter) does.

    use Importer 'Some::Thing'  => ':DEFAULT';

    use Importer 'Other::Thing' => ':some_tag';

Tags can be specified this way:

    our %EXPORT_TAGS = (
        oos => [qw/foo boo zoo/],
        ees => [qw/fee bee zee/],
    );

## @EXPORT\_FAIL

This is used exactly the way [Exporter](https://metacpan.org/pod/Exporter) uses it.

Use this to list subs that are not available on all platforms. If someone tries
to import one of these, Importer will hit your `$from->export_fail(@items)`
callback to try to resolve the issue. See [Exporter](https://metacpan.org/pod/Exporter)
for documentation of
this feature.

    our @EXPORT_FAIL = qw/maybe_bad/;

## %EXPORT\_ANON

This is new to this module, [Exporter](https://metacpan.org/pod/Exporter) does not support it.

This allows you to export symbols that are not actually in your package symbol
table. The keys should be the symbol names, the values are the references for
the symbols.

    our %EXPORT_ANON = (
        '&foo' => sub { 'foo' }
        '$foo' => \$foo,
        ...
    );

## %EXPORT\_GEN

This is new to this module, [Exporter](https://metacpan.org/pod/Exporter) does not support it.

This allows you to export symbols that are generated on export. The key should
be the name of a symbol. The value should be a coderef that produces a
reference that will be exported.

When the generators are called they will receive 2 arguments, the package the
symbol is being exported into, and the symbol being imported (name may or may
not include sigil for subs).

    our %EXPORT_GEN = (
        '&foo' => sub {
            my $from_package = shift;
            my ($into_package, $symbol_name) = @_;
            ...
            return sub { ... };
        },
        ...
    );

## %EXPORT\_MAGIC

This is new to this module. [Exporter](https://metacpan.org/pod/Exporter) does not support it.

This allows you to define custom actions to run AFTER an export has been
injected into the consumers namespace. This is a good place to enable parser
hooks like with [Devel::Declare](https://metacpan.org/pod/Devel::Declare). These
will NOT be run if a consumer uses a
custom assignment callback.

    our %EXPORT_MAGIC = (
        foo => sub {
            my $from = shift;    # Should be the package doing the exporting
            my %args = @_;

            my $into      = $args{into};         # Package symbol was exported into
            my $orig_name = $args{orig_name};    # Original name of the export (in the exporter)
            my $new_name  = $args{new_name};     # Name the symbol was imported as
            my $ref       = $args{ref};          # The reference to the symbol

            ...; # whatever you want, return is ignored.
        },
    );

# CLASS METHODS

- Importer->import($from)
- Importer->import($from, $version)
- Importer->import($from, @imports)
- Importer->import($from, $from\_version, @imports)
- Importer->import($importer\_version, $from, ...)

    This is the magic behind `use Importer ...`.

- Importer->import\_into($from, $into, @imports)
- Importer->import\_into($from, $level, @imports)

    You can use this to import symbols from `$from` into `$into`. `$into` may
    either be a package name, or a caller level to get the name from.

- Importer->unimport()
- Importer->unimport(@sub\_name)

    This is the magic behind `no Importer ...`.

- Importer->unimport\_from($from, @sub\_names)
- Importer->unimport\_from($level, @sub\_names)

    This lets you remove imported symbols from `$from`. `$from` my be a package
    name, or a caller level.

- my $exports = Importer->get($from, @imports)

    This returns hashref of `{ $name => $ref }` for all the specified imports.

    `$from` should be the package from which to get the exports.

- my @export\_refs = Importer->get\_list($from, @imports)

    This returns a list of references for each import specified. Only the export
    references are returned, the names are not.

    `$from` should be the package from which to get the exports.

- $export\_ref = Importer->get\_one($from, $import)

    This returns a single reference to a single export. If you provide multiple
    imports then only the LAST one will be used.

    `$from` should be the package from which to get the exports.

# USING WITH OTHER EXPORTER IMPLEMENTATIONS

If you want your module to work with Importer, but you use something other than
[Exporter](https://metacpan.org/pod/Exporter) to define your exports, you can make
it work be defining the
`IMPORTER_MENU` method in your package. As well other exporters can be updated
to support Importer by putting this sub in your package.
**IMPORTER\_MENU() must be defined in your package, not a base class!**

    sub IMPORTER_MENU {
        my $class = shift;
        my ($into, $caller) = @_;

        return (
            export       => \@EXPORT,          # Default exports
            export_ok    => \@EXPORT_OK,       # Other allowed exports
            export_tags  => \%EXPORT_TAGS,     # Define tags
            export_fail  => \@EXPORT_FAIL,     # For subs that may not always be available
            export_anon  => \%EXPORT_ANON,     # Anonymous symbols to export
            export_magic => \%EXPORT_MAGIC,    # Magic to apply after a symbol is exported

            generate   => \&GENERATE,          # Sub to generate dynamic exports
                                               # OR
            export_gen => \%EXPORT_GEN,        # Hash of builders, key is symbol
                                               # name, value is sub that generates
                                               # the symbol ref.
        );
    }

    sub GENERATE {
        my ($symbol) = @_;

        ...

        return $ref;
    }

All exports must be listed in either `@EXPORT` or `@EXPORT_OK`, or be keys in
`%EXPORT_GEN` or `%EXPORT_ANON` to be allowed. 'export\_tags', 'export\_fail',
'export\_anon', 'export\_gen', and 'generate' are optional. You cannot combine
'generate' and 'export\_gen'.

**Note:** If your GENERATE sub needs the `$class`, `$into`, or `$caller` then
your `IMPORTER_MENU()` method will need to build an anonymous sub that closes
over them:

    sub IMPORTER_MENU {
        my $class = shift;
        my ($into, $caller) = @_;

        return (
            ...
            generate => sub { $class->GENERATE($into, $caller, @_) },
        );
    }

# OO Interface

    use Importer;

    my $imp = Importer->new(from => 'Some::Exporter');

    $imp->do_import('Destination::Package');
    $imp->do_import('Another::Destination', @symbols);

Or, maybe more useful:

    my $imp = Importer->new(from => 'Carp');
    my $croak = $imp->get_one('croak');
    $croak->("This will croak");

## OBJECT CONSTRUCTION

- $imp = Importer->new(from => 'Some::Exporter')
- $imp = Importer->new(from => 'Some::Exporter', caller => \[$package, $file, $line\])

    This is how you create a new Importer instance. `from => 'Some::Exporter'`
    is the only required argument. You may also specify the `caller => [...]`
    arrayref, which will be used only for error reporting. If you do not specify a
    caller then Importer will attempt to find the caller dynamically every time it
    needs it (this is slow and expensive, but necessary if you intend to re-use the
    object.)

## OBJECT METHODS

- $imp->do\_import($into)
- $imp->do\_import($into, @symbols)

    This will import from the objects `from` package into the `$into` package.
    You can provide a list of `@symbols`, or you can leave it empty for the
    defaults.

- $imp->do\_unimport()
- $imp->do\_unimport(@symbols)

    This will remove imported symbols from the objects `from` package. If you
    specify a list of `@symbols` then only the specified symbols will be removed,
    otherwise all symbols imported using Importer will be removed.

    **Note:** Please be aware of the difference between `do_import()` and
    `do_unimport()`. For import 'from' us used as the origin, in unimport it is
    used as the target. This means you cannot re-use an instance to import and then
    unimport.

- ($into, $versions, $exclude, $symbols, $set) = $imp->parse\_args('Dest::Package')
- ($into, $versions, $exclude, $symbols, $set) = $imp->parse\_args('Dest::Package', @symbols)

    This parses arguments. The first argument must be the destination package.
    Other arguments can be a mix of symbol names, tags, patterns, version numbers,
    and exclusions.

- $caller\_ref = $imp->get\_caller()

    This will find the caller. This is mainly used for error reporting. IF the
    object was constructed with a caller then that is what is returned, otherwise
    this will scan the stack looking for the first call that does not originate
    from a package that ISA Importer.

- $imp->carp($warning)

    Warn at the callers level.

- $imp->croak($exception)

    Die at the callers level.

- $from\_package = $imp->from()

    Get the `from` package that was specified at construction.

- $file = $imp->from\_file()

    Get the filename for the `from` package.

- $imp->load\_from()

    This will load the `from` package if it has not been loaded already. This uses
    some magic to ensure errors in the load process are reported to the `caller`.

- $menu\_hr = $imp->menu($into)

    Get the export menu built from, or provided by the `from` package. This is
    cached after the first time it is called. Use `$imp->reload_menu()` to
    refresh it.

    The menu structure looks like this:

        $menu = {
            # every valid export has a key in the lookup hashref, value is always
            # 1, key always includes the sigil
            lookup => {'&symbol_a' => 1, '$symbol_b' => 1, ...},

            # most exports are listed here, symbol name with sigil is key, value is
            # a reference to the symbol. If a symbol is missing it may be generated.
            exports => {'&symbol_a' => \&symbol_a, '$symbol_b' => \$symbol_b, ...},

            # Hashref of tags, tag name (without ':' prefix) is key, value is an
            # arrayref of symbol names, subs may have a sigil, but are not required
            # to.
            tags => { DEFAULT => [...], foo => [...], ... },

            # Magic to apply
            magic => { foo => sub { ... }, ... },

            # This is a hashref just like 'lookup'. Keys are symbols which may not
            # always be available. If there are no symbols in this category then
            # the value of the 'fail' key will be undef instead of a hashref.
            fail => { '&iffy_symbol' => 1, '\&only_on_linux' => 1 },
            # OR fail => undef,

            # If present, this subroutine knows how to generate references for the
            # symbols listed in 'lookup', but missing from 'exports'. References
            # this returns are NEVER cached.
            generate => sub { my $sym_name = shift; ...; return $symbol_ref },
        };

- $imp->reload\_menu($into)

    This will reload the export menu from the `from` package.

- my $exports = $imp->get(@imports)

    This returns hashref of `{ $name => $ref }` for all the specified imports.

- my @export\_refs = $imp->get\_list(@imports)

    This returns a list of references for each import specified. Only the export
    references are returned, the names are not.

- $export\_ref = $imp->get\_one($import)

    This returns a single reference to a single export. If you provide multiple
    imports then only the LAST one will be used.

# FUNCTIONS

These can be imported:

    use Importer 'Importer' => qw/import optimal_import/;

- $bool = optimal\_import($from, $into, \\@caller, @imports)

    This function will attempt to import `@imports` from the `$from` package into
    the `$into` package. `@caller` needs to have a package name, filename, and
    line number. If this function fails then no exporting will actually happen.

    If the import is successful this will return true.

    If the import is unsuccessful this will return false, and no modifications to
    the symbol table will occur.

- $class->import(@imports)

    If you write class intended to be used with [Importer](https://metacpan.org/pod/Importer),
    but also need to
    provide a legacy `import()` method for direct consumers of your class, you can
    import this `import()` method.

        package My::Exporter;

        # This will give you 'import()' much like 'use base "Exporter";'
        use Importer 'Importer' => qw/import/;

        ...

# SOURCE

The source code repository for Importer can be found at
[http://github.com/exodist/Importer](http://github.com/exodist/Importer).

# MAINTAINERS

- Chad Granum <exodist@cpan.org>

# AUTHORS

- Chad Granum <exodist@cpan.org>

# COPYRIGHT

Copyright 2015 Chad Granum <exodist7@gmail.com>.

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

See [http://dev.perl.org/licenses/](http://dev.perl.org/licenses/)

========================================================================
* LICENSE
========================================================================

This software is copyright (c) 2020 by Chad Granum.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

Terms of the Perl programming language system itself

a) the GNU General Public License as published by the Free
   Software Foundation; either version 1, or (at your option) any
   later version, or
b) the "Artistic License"

--- The GNU General Public License, Version 1, February 1989 ---

This software is Copyright (c) 2020 by Chad Granum.

This is free software, licensed under:

  The GNU General Public License, Version 1, February 1989

                    GNU GENERAL PUBLIC LICENSE
                     Version 1, February 1989

 Copyright (C) 1989 Free Software Foundation, Inc.
 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

                            Preamble

  The license agreements of most software companies try to keep users
at the mercy of those companies.  By contrast, our General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users.  The
General Public License applies to the Free Software Foundation's
software and to any other program whose authors commit to using it.
You can use it for your programs, too.

  When we speak of free software, we are referring to freedom, not
price.  Specifically, the General Public License is designed to make
sure that you have the freedom to give away or sell copies of free
software, that you receive source code or can get it if you want it,
that you can change the software or use pieces of it in new free
programs; and that you know you can do these things.

  To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.

  For example, if you distribute copies of a such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have.  You must make sure that they, too, receive or can get the
source code.  And you must tell them their rights.

  We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.

  Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software.  If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.

  The precise terms and conditions for copying, distribution and
modification follow.

                    GNU GENERAL PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. This License Agreement applies to any program or other work which
contains a notice placed by the copyright holder saying it may be
distributed under the terms of this General Public License.  The
"Program", below, refers to any such program or work, and a "work based
on the Program" means either the Program or any work containing the
Program or a portion of it, either verbatim or with modifications.  Each
licensee is addressed as "you".

  1. You may copy and distribute verbatim copies of the Program's source
code as you receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy an appropriate copyright notice and
disclaimer of warranty; keep intact all the notices that refer to this
General Public License and to the absence of any warranty; and give any
other recipients of the Program a copy of this General Public License
along with the Program.  You may charge a fee for the physical act of
transferring a copy.

  2. You may modify your copy or copies of the Program or any portion of
it, and copy and distribute such modifications under the terms of Paragraph
1 above, provided that you also do the following:

    a) cause the modified files to carry prominent notices stating that
    you changed the files and the date of any change; and

    b) cause the whole of any work that you distribute or publish, that
    in whole or in part contains the Program or any part thereof, either
    with or without modifications, to be licensed at no charge to all
    third parties under the terms of this General Public License (except
    that you may choose to grant warranty protection to some or all
    third parties, at your option).

    c) If the modified program normally reads commands interactively when
    run, you must cause it, when started running for such interactive use
    in the simplest and most usual way, to print or display an
    announcement including an appropriate copyright notice and a notice
    that there is no warranty (or else, saying that you provide a
    warranty) and that users may redistribute the program under these
    conditions, and telling the user how to view a copy of this General
    Public License.

    d) You may charge a fee for the physical act of transferring a
    copy, and you may at your option offer warranty protection in
    exchange for a fee.

Mere aggregation of another independent work with the Program (or its
derivative) on a volume of a storage or distribution medium does not bring
the other work under the scope of these terms.

  3. You may copy and distribute the Program (or a portion or derivative of
it, under Paragraph 2) in object code or executable form under the terms of
Paragraphs 1 and 2 above provided that you also do one of the following:

    a) accompany it with the complete corresponding machine-readable
    source code, which must be distributed under the terms of
    Paragraphs 1 and 2 above; or,

    b) accompany it with a written offer, valid for at least three
    years, to give any third party free (except for a nominal charge
    for the cost of distribution) a complete machine-readable copy of the
    corresponding source code, to be distributed under the terms of
    Paragraphs 1 and 2 above; or,

    c) accompany it with the information you received as to where the
    corresponding source code may be obtained.  (This alternative is
    allowed only for noncommercial distribution and only if you
    received the program in object code or executable form alone.)

Source code for a work means the preferred form of the work for making
modifications to it.  For an executable file, complete source code means
all the source code for all modules it contains; but, as a special
exception, it need not include source code for modules which are standard
libraries that accompany the operating system on which the executable
file runs, or for standard header files or definitions files that
accompany that operating system.

  4. You may not copy, modify, sublicense, distribute or transfer the
Program except as expressly provided under this General Public License.
Any attempt otherwise to copy, modify, sublicense, distribute or transfer
the Program is void, and will automatically terminate your rights to use
the Program under this License.  However, parties who have received
copies, or rights to use copies, from you under this General Public
License will not have their licenses terminated so long as such parties
remain in full compliance.

  5. By copying, distributing or modifying the Program (or any work based
on the Program) you indicate your acceptance of this license to do so,
and all its terms and conditions.

  6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the original
licensor to copy, distribute or modify the Program subject to these
terms and conditions.  You may not impose any further restrictions on the
recipients' exercise of the rights granted herein.

  7. The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

Each version is given a distinguishing version number.  If the Program
specifies a version number of the license which applies to it and "any
later version", you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation.  If the Program does not specify a version number of
the license, you may choose any version ever published by the Free Software
Foundation.

  8. If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission.  For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this.  Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.

                            NO WARRANTY

  9. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.

  10. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.

                     END OF TERMS AND CONDITIONS

        Appendix: How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to humanity, the best way to achieve this is to make it
free software which everyone can redistribute and change under these
terms.

  To do so, attach the following notices to the program.  It is safest to
attach them to the start of each source file to most effectively convey
the exclusion of warranty; and each file should have at least the
"copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) 19yy  <name of author>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 1, or (at your option)
    any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 USA


Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:

    Gnomovision version 69, Copyright (C) 19xx name of author
    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the
appropriate parts of the General Public License.  Of course, the
commands you use may be called something other than `show w' and `show
c'; they could even be mouse-clicks or menu items--whatever suits your
program.

You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary.  Here a sample; alter the names:

  Yoyodyne, Inc., hereby disclaims all copyright interest in the
  program `Gnomovision' (a program to direct compilers to make passes
  at assemblers) written by James Hacker.

  <signature of Ty Coon>, 1 April 1989
  Ty Coon, President of Vice

That's all there is to it!


--- The Artistic License 1.0 ---

This software is Copyright (c) 2020 by Chad Granum.

This is free software, licensed under:

  The Artistic License 1.0

The Artistic License

Preamble

The intent of this document is to state the conditions under which a Package
may be copied, such that the Copyright Holder maintains some semblance of
artistic control over the development of the package, while giving the users of
the package the right to use and distribute the Package in a more-or-less
customary fashion, plus the right to make reasonable modifications.

Definitions:

  - "Package" refers to the collection of files distributed by the Copyright
    Holder, and derivatives of that collection of files created through
    textual modification.
  - "Standard Version" refers to such a Package if it has not been modified,
    or has been modified in accordance with the wishes of the Copyright
    Holder.
  - "Copyright Holder" is whoever is named in the copyright or copyrights for
    the package.
  - "You" is you, if you're thinking about copying or distributing this Package.
  - "Reasonable copying fee" is whatever you can justify on the basis of media
    cost, duplication charges, time of people involved, and so on. (You will
    not be required to justify it to the Copyright Holder, but only to the
    computing community at large as a market that must bear the fee.)
  - "Freely Available" means that no fee is charged for the item itself, though
    there may be fees involved in handling the item. It also means that
    recipients of the item may redistribute it under the same conditions they
    received it.

1. You may make and give away verbatim copies of the source form of the
Standard Version of this Package without restriction, provided that you
duplicate all of the original copyright notices and associated disclaimers.

2. You may apply bug fixes, portability fixes and other modifications derived
from the Public Domain or from the Copyright Holder. A Package modified in such
a way shall still be considered the Standard Version.

3. You may otherwise modify your copy of this Package in any way, provided that
you insert a prominent notice in each changed file stating how and when you
changed that file, and provided that you do at least ONE of the following:

  a) place your modifications in the Public Domain or otherwise make them
     Freely Available, such as by posting said modifications to Usenet or an
     equivalent medium, or placing the modifications on a major archive site
     such as ftp.uu.net, or by allowing the Copyright Holder to include your
     modifications in the Standard Version of the Package.

  b) use the modified Package only within your corporation or organization.

  c) rename any non-standard executables so the names do not conflict with
     standard executables, which must also be provided, and provide a separate
     manual page for each non-standard executable that clearly documents how it
     differs from the Standard Version.

  d) make other distribution arrangements with the Copyright Holder.

4. You may distribute the programs of this Package in object code or executable
form, provided that you do at least ONE of the following:

  a) distribute a Standard Version of the executables and library files,
     together with instructions (in the manual page or equivalent) on where to
     get the Standard Version.

  b) accompany the distribution with the machine-readable source of the Package
     with your modifications.

  c) accompany any non-standard executables with their corresponding Standard
     Version executables, giving the non-standard executables non-standard
     names, and clearly documenting the differences in manual pages (or
     equivalent), together with instructions on where to get the Standard
     Version.

  d) make other distribution arrangements with the Copyright Holder.

5. You may charge a reasonable copying fee for any distribution of this
Package.  You may charge any fee you choose for support of this Package. You
may not charge a fee for this Package itself. However, you may distribute this
Package in aggregate with other (possibly commercial) programs as part of a
larger (possibly commercial) software distribution provided that you do not
advertise this Package as a product of your own.

6. The scripts and library files supplied as input to or produced as output
from the programs of this Package do not automatically fall under the copyright
of this Package, but belong to whomever generated them, and may be sold
commercially, and may be aggregated with this Package.

7. C or perl subroutines supplied by you and linked into this Package shall not
be considered part of this Package.

8. The name of the Copyright Holder may not be used to endorse or promote
products derived from this software without specific prior written permission.

9. THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

The End